"""
三角形面积
"""
import math
a, b, c = input().split()
a, b, c = int(a),int(b),int(c)
if a + b <= c or a + c <= b or b + c <= a:
    print('These sides do not correspond to a valid triangle')
else:
    perimeter = a+b+c
    s = perimeter/2
    area = math.sqrt(s*(s-a)*(s-b)*(s-c))
    print('area = %.2f; perimeter = %.2f' %(area,perimeter))